Heater



FIG. 1 is a front, right, perspective view of the heater;

FIG. 2 is a front view thereof;

FIG. 3 is a left side view thereof; and,

FIG. 4 is a top view thereof.

The broken lines are for illustrative purposes only and form no part ofthe claimed design.

I claim the ornamental design for a heater, as shown and described.